Apparatus for forming centrifugally cast linings



March '10, 1942. -w. BRbwN 2,275,504

APPARATUS FOR FORMING CENTRIFUGALLY CAST IIJININGS f Filed Sept. 22, 1959 J N. (9 (9 LL. LI.

E I I m h Q LL INVENTOR.-

I ATTORNEYS 1 FIGJQ Patented Mar. 10, 1942 UNITED. STATES PATENT mm:

APPARATUS FOR FORMING CENTRIFU- GALLY cAs'r LININGS Walter Brawn, Toledo, Ohio Application September 22, 1939, Serial No. 296,156 6 Claims. (0l. 22203) The invention relates to the manufacture of composite metal articles composed of two different metals or alloys integrally and continuously bonded together. More particularly, the invention relates to the lining of a preformed metal article either on the inner or the outer surfaces thereof, or on both inner and outer surfaces.

The invention is an improvement on the invention described and claimed in my Patent No., 1,923,075, issued August 22, 1933, and on my copending application, Serial No. 56,045, filed December 24, 1935.

In the present state of the art, as shown by my prior patent and pending application above referred to, it is. possible to form an integral and continuous bond between metals and alloys of relatively high melting point and preformed metal articles such'as shafts and tubes. Essentially the process consists of forming a tubular" shell which is hermetically sealed except for a 'heating furnace and brought to a temperature which will cause the lining metal to become molperiod of time, very little contaminating material can be picked up by the molten metal. My invention may be carried out in various diflferent ways which are hereinafter more fully described and illustrated in the accompanying drawing, wherein- Figure 1 is a longitudinal section through a tube inwhich a lining is to be formed showing the method of inserting the lining material and preparing the tube for the lining process;

Figure 2 is a diagrammatic view showing the method of spinning the tube of Figure 1;

Figure 3 is a crosssection through the tube of Figure 1 after spinning;

Figure 4 is a longitudinal section through an assembly for lining the outer surface of a tubular article; v

Figure 5 is a longitudinal section through an assembly for lining both the outer and. inner surfaces of bearing shells to form bearings for interna'l combustion engines;

ten and then the heated assembly is placed in a spinning machine which centrifugally distributes the molten metal until it solidifies and forms the composite article. In the-prior methods it has been found that the molten lining metal steel, the lining metal becomes alloyed with a certain amount of iron which in some cases is detrimental to the quality of the lining metal in the finished article. i

The principal object of this invention is to prevent any substantial contamination of the molten lining metal during the process. To this end I have devised aprocess whereby the lining metal is' retained within a container during the heating stage of the process and is not allowed to come in contact with the article to which it 'is to be bonded until the assembly is'in condition for the final spinning operation. .The container for-the molten metal is formed of a materialwhich will 'not contaminate the lining metal when the latter in. a molten condition, and thus the molten this latter operation requires a relatively short Figure 6 is a cross section on the line 66 of Figure5; j

Figure 7 is a cross section of the finished bearing made with the assembly of Figure 5.;

\ Figure "8 is a longitudinal section through a modified arrangement for lining the outer surface of a solid shaft.

lining of hollow tubes on the inside surface only.

, l0 represents the tube to be lined and H and I2 are end plates secured to the tube, preferably by welding as indicated at I3. One of the end plates tube.

has a small venthole I4 which permits the escape of the oxidizing gases during the heating operation and also permits or the introduction of mashort piece of tubing I5 which forms a retainer for the container l6 which is concentric with the outer tube Ill. The container I6 is of a size tohold suflicient lining metal to provide for a lining of the desired thickness and, as shown, it extends lengthwise within the outer tube for asubstantial proportion of the total length of the outer The container I6 is formed of a material which is inert to the action of the molten lining metal, or at least does not introduce constituents into the molten lining metal which are detrimental to the properties desired. The con tainer' may be made, for example, of graphite or porcelain, or any other ceramic material which will remain solid at the temperatures used during the process and at the' same time will not revvent gravity flow out of the container.

act with the molten metal to form undesirable impuritiestherein. Y

The lining metal is introduced into the container IS in the solid state in any desired form which is convenient for loading within the containein- It is represented by the numeral ll.

- After introducing the solid metal, the end plate Thus the assembly should be heated while in a vertical position or at a suflicient incline to pre- After the assembly has been heated to the desired temperature, .it is withdrawn from the furnace and placed in a spinning machine as diagrammatically illustrated in Figure 2. The molten metal then flows by gravity into the bottom of the tube Ill, but the machine is immediately set in operation to centrifugally distribute the molten metal so that it uniformly lines the walls of the tube.

The spinning is continued until the metal solidities and it is usual to hasten the solidification by external cooling as by projecting a series of streams of water onto the spinning tube. When the spinning is complete, the tube is removed from the machine, the end plates and the container it are severed from the tube, thus leaving the composite metal tubing as illustratedv in Figure 3 where l8 represents the inner lining bonded to the outer tube I B.

With the arrangement as described, it will,be apparent that the molten material is in contact with the walls of the tube GB for a very aavasoa is inserted within an outer shell 32 and welded thereto by means of the spacer ring 33. The free end of the shaft 3! is held concentric within the shell by a perforated spacer 34 which engages the outersurface of the shaft 3!, leaving the same free for expansion in a longitudinal direction. The shell 32 extends beyond the end of the shaft and has formed within the same a container 35 of sufilcient size to hold the required short period of time and this prevents any substantial amount ofimpurities being picked up from the walls of the tube.

Where it is desired to line the outer surface of a tubular article, an assembly as shown in Figure 4 is provided.- I9 is the tubular article to be lined and 20 is a relatively thin outer shell. In

order to keep the tube and shell concentric, the

. end plates 2| are provided with cylindrical portions 22 which engage the inner surface, of the lined comprising an outer shell, end plates for said outer shell, and a container for the lining tube l9. The tube to be lined is provided with perforations 23 to permit the molten metal to be centrifugally distributed into the annular space 24 between the tube and the outer shell. Qne of the end plates 2! is provided with a cylindrical retainer I5 for receiving a container l6 in the same manner as previouslydescribed. Thus by heating the assembly while in a vertical position, the lining metal is retained within the container and the assembly is not placed in a horizontal position until it is entirely ready for spinning so that the molten material has only a momentary contact with the tube and the shell prior to the completion of the casting operation ing both the inner and outer surfaces of tubular shells as shown in Figure 5. In this modificaspacer rings '28. Slots 30 in the steel inserts permit the moltenmetal to be distributed to the outer surfaces of. the inserts. Suificient lining metal is introduced within the'co'ntainer IE to form thedesired thickness of lining metal on both the outer and inner surfaces.

Figure 8 shows a modified form of assembly for centrifugally coating a lining metal on the outer surface of a solid shaft. As shown, the shaft au -60 My improved process may also be used for linamount of lining metal.

formed of an inert material as previously described. To provide a vent for the escape of, gases within the shell, the shaft may be drilledv as indicated at 36 and 31.

With this modification, the assembly must be heated in a vertical position and retained in this position until the assembly is ready for spinning, thus preventing the molten metal from contamination prior to the spinning operation.

What I claim as my invention is: 1. An assembly for lining articles which com prises an outer shell, a container concentrically arranged within said shell for receiving solid lining material, said container being composed of a material which will not contaminate the lincured tosaid tube, means for venting said tube, a

cylindrical retaining tube within said outer tube and secured to one of said end plates; and a cone tainer for the lining material supported within said retainer and extending concentrically with said outer tube, said container being composed of a material which will not contaminate the lining metal when the latter is in the molten con dition.

3. An assembly for. the centrifugal casting of a lining metal on the surface of an article to be material also within said outer shell, said container being composed of a material which will not contaminate the lining metal when the latter is in the molten state.

4. An assembly for lining articles comprising 'an outer shell adapted to receive a tubular article concentrically arranged within the same, a

tubular container within said tubular article, said container being composed of a material whichv will not contaminate the lining metal when the latter is in the molten state, and means for substahtially sealing the" ends of said shell- 5. An assembly for lining articles whichcomprises an outer shell, means for substantially sealing said shell, 9. container for receiving solid lining material in communication with said, sealed outer shell and concentric therewith, said container being composed of amaterial which will not'contaminate the lining material when the latteris in the molten condition.

6. An assembly for castinga molten metal onto, a'solid metal article comprising an outer cylindrical metallic shell adapted to receive a solid metal article a ceramic container wi hin said shell adapted to hold the molten metal to be cast out of contact'with said article until the assembly is at the proper temperature for casting, and means for substantially sealing said outer :shell to exclude the outside atmosphere during heating and casting. WALTER BROWN.

This container is for lining articles which com- 

